title: Combined N-glycome and N-glycoproteome analysis of the Lotus japonicus seed globulin fraction shows conservation of protein structure and glycosylation in legumes.
abstract: Legume food allergy, such as allergy toward peanuts and soybeans, is a health issue predicted to worsen as dietary advice recommends higher intake of legume-based foods. Lotus japonicus (Lotus) is an established legume plant model system for studies of symbiotic and pathogenic microbial interactions and, due to its well characterized genotype/phenotype and easily manipulated genome, may also be suitable for studies of legume food allergy. Here we present a comprehensive study of the Lotus N-glycoproteome. The global and site-specific N-glycan structures of Lotus seed globulins were analyzed using mass spectrometry-based glycomics and glycoproteomics techniques. In total, 19 N-glycan structures comprising high mannose (∼20%), pauci-mannosidic (∼40%), and complex forms (∼40%) were determined. The pauci-mannosidic and complex N-glycans contained high amounts of the typical plant determinants β-1,2-xylose and α-1,3-fucose. Two abundant Lotus seed N-glycoproteins were site-specifically profiled; a predicted lectin containing two fully occupied N-glycosylation sites carried predominantly pauci-mannosidic structures in different distributions. In contrast, Lotus convicilin storage protein 2 (LCP2) carried exclusively high mannose N-glycans similar to its homologue, Ara h 1, which is the major allergen in peanut. In silico investigation confirmed that peanut Ara h 1 and Lotus LCP2 are highly similar at the primary and higher protein structure levels. Hence, we suggest that Lotus has the potential to serve as a model system for studying the role of seed proteins and their glycosylation in food allergy.
authors.affiliation: Centre for Carbohydrate Recognition and Signalling, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
authors.forename: Svend
authors.initials: S
authors.lastname: Dam
authors.forename: Morten
authors.initials: M
authors.lastname: Thaysen-Andersen
authors.forename: Eva
authors.initials: E
authors.lastname: Stenkjær
authors.forename: Andrea
authors.initials: A
authors.lastname: Lorentzen
authors.forename: Peter
authors.initials: P
authors.lastname: Roepstorff
authors.forename: Nicolle H
authors.initials: NH
authors.lastname: Packer
authors.forename: Jens
authors.initials: J
authors.lastname: Stougaard
mesh_terms: D017124:Conserved Sequence; D005916:Globulins / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D006023:Glycoproteins / Q000302:isolation & purification* / Q000378:metabolism; D006031:Glycosylation; D000070116:Lotus / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012639:Seeds / Q000378:metabolism
chemical_list: D005916:Globulins; D006023:Glycoproteins; D010940:Plant Proteins